As a technology for allowing unmanned vehicles and a manned vehicle to exist and travel together, Patent Document 1 discloses: “The vehicle control device (mounted on each unmanned vehicle) controls the steering angle, brakes, transmission and engine rotation speed on the basis of the data on the current position and the current velocity of the vehicle measured by the position measurement device, the command data to indicate such commands as stop and deceleration from the monitoring station received by the monitoring station-vehicle communication device, the control data to indicate such control commands as deceleration received from another vehicle via the inter-vehicle communication device, the detection signal of the obstacle sensor, and the course data stored in the course data storage device. In other words, the target engine rotation speed is set, and the fuel oil consumption is controlled according to the electric signals to be applied to an electronic control governor to change the engine rotation speed . . . the manned vehicle has a display for displaying the content of the instruction data, such as instructions on the target position of the vehicle and the course to travel (predetermined traveling path), instructions to stop, instructions to decelerate transmitted from the monitoring station, and later mentioned control command data, which is input from another vehicle via the inter-vehicle communication device, and in normal cases, the operator controls various predetermined operations according to the content displayed on this display, and the operator manually controls the steering angle, brake, transmission and engine rotation speed. (extracted from the specification)”.